Search Results for compression-after-impact testing

Measuring material properties is disproportionately more complex for fiber-reinforced composites than for materials such as metals and plastics. It is further complicated by more than 150 composite test standards in use around the globe. This article assesses the challenges involved in testing fiber-reinforced composites and presents a rational approach for specimen preparation, handling, and fixturing that can simplify testing and improve throughput without sacrificing measurement accuracy.

Successful use of composite materials requires a thorough understanding of their mechanical properties. Although a range of mechanical tests is required to obtain data, the aerospace industry has already developed, validated, and standardized these test methods. This article reviews some of key test methods used with composites.

Simulating bird-plane collisions helps aviation engineers design safer aerostructures and reduce physical testing.

This article compares two nondestructive test methods that are widely used to assess impact damage in carbon fiber-reinforced polymer composites. Infrared line scanning thermography (LST) and immersion ultrasonic testing (UT) are shown to be equally capable of detecting delaminations and internal cracking caused by low-velocity impacts, although LST was easier to use and provided results more quickly that were easier to interpret.

Wire arc directed energy deposition (WDED) is a robust alternative for large-scale metal printing. It offers high deposition rates, excellent material and energy efficiency, and reduced waste material compared to conventional manufacturing processes. This article describes a study that employed a combination of standard and advanced characterization techniques to assess the mechanical behavior of WDED titanium samples. This entry won first place in the light microscopy category of the prestigious 2023 International Metallographic Contest.

Nanostructured tungsten-tungsten carbide chemical vapor deposition (CVD) coatings provide a practical, technical, and commercially viable alternative to hard chrome plating for aircraft components.

For sports and recreation equipment manufacturers and sports medicine clinicians, mechanical testing is essential to optimize material performance, minimize injury, and improve recovery outcomes. This article describes some of the specialized tests used for sports equipment.

The ability to produce bulk metallic nanolaminates has greatly expanded the potential structural applications for these materials, motivating investigations into formability, joining techniques, and deformation behavior. This article presents an overview of both the accumulative roll bonding process and the deformation behavior for copper-niobium nanolaminates. This entry won the Jacquet-Lucas Award for Best in Show at the 2014 International Metallographic Contest.

Many companies are revisiting their decision to bring materials testing in-house. This article reviews quality, time, and cost factors involved in analyzing in-house versus outsourced testing approaches.

Residual stress exists in all classes of materials and significantly impacts many facets of product design and manufacturing. This article reviews residual stress formation, types of stresses, and measurement techniques. ASM International is launching a technical committee on residual stress to enable industry-wide collabration and to advance the science of this important phenomenon.

This article discusses the development and use of a nondestructive evaluation (NDE) method that allows researchers to compare surface crystallographic orientations before and after mechanical testing to determine the impact of surface orientation on material response. Two gage samples were tested, one rectangular (Ti-Al), the other round (IN100). The samples were placed in a SEM equipped with an EBSD detector and a motorized fixture that rotates the test piece as EBSD and imaging data are collected. Inverse pole figure maps of both gage samples are presented.

Tests conducted on vacuum carburized and quenched shafts identify variables that increase distortion and the magnitude of residual stresses.

This article describes research aimed at developing cast aluminum alloys with the necessary high-temperature tensile and fatigue strengths to withstand the modern automotive engine environment. Micro-additions of Ti, V, and Zr were added to an Al-7Si-1Cu-0.5Mg cast alloy, leading to the formation of phases that increase stability at high temperatures, positively affecting alloy strength.

Coating development using cold gas spray technology demonstrates the feasibility of bonding polymers to metal substrates and metals to polymer composite substrates with good adhesion. The examples addressed are polyetheretherketone (PEEK) coatings on steel and aluminum substrates and metallic coatings on carbon fiber reinforced polymer (CFRP) composites.

Researchers at MIT have evaluated a wide range of helmet liner designs and materials for potential use in the U.S. Army's advanced combat helmet (ACH). To measure the effectiveness of candidate materials, the investigators rely on finite-element simulations that are validated by shock tube testing at Purdue University. Of the various filler materials examined, glass beads, glycerin, and water show the most promise for blast attenuation.

Beyond automotive, aerospace, and medical materials innovations, research and development of advanced materials and processes for sports and recreation activities is one of the most exciting areas for today’s materials scientists and engineers. This article compiles examples of materials innovations in equipment for cycling, ice skating, cricket, running, football, sailing, and fishing.

Software specifically designed for materials testing environments and quality control laboratories offers a solution to many of today’s challenges, including lightweighting initiatives across multiple industries.This article describes commercial software available for managing test programs and regulatory compliance.

While today's composites encompass a broad and well-established family of materials, the commercial market for high-performance, structural composites has actually existed for well over 30 years. Adoption in the aerospace industry has resulted in a wide range of static test methods offering reliable results. This article reviews some recent innovations in composites testing, including developments related to fatigue testing, high strain rate testing, thermography, and high capacity test systems.

Both shape memory and elastocaloric effects are related to the reversible martensitic phase transformation. For the shape memory effect, thermal energy is used to drive the material through the phase transformation and recover its original shape. For the elastocaloric effect, mechanical energy is used to induce phase transformation, and the associated latent heat is used to pump heat for cooling or heating. Heat pumps based on the elastocaloric effect have a low environmental impact and are highly efficient. However, designing a prototype to harvest the full potential of the elastocaloric effect has been challenging. This article summarizes prototyping efforts undertaken by three different research groups.

Selecting materials for high-pressure hydrogen systems requires balancing technical understanding of hydrogen embrittlement and business considerations. While the direct effect of hydrogen on materials is usually manifested as ductility loss under tension stress, the most concerning failure in a hydrogen system is fatigue. Although no material is immune to property degradation caused by hydrogen, Type 316 stainless steel is among the best in resisting hydrogen embrittlement.